[clang] [AMDGPU] Correctly pass the target-id to `ld.lld` (PR #101037)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/101037

Summary:
The `ld.lld` linker handles LTO, but it does not understand the
target-id syntax some AMDGPU targets use. This patch parses the
target-id and passes the processor name in `-mcpu` and features in
`-mattr`.


>From e2ebb324de6a486c106868b92aad3f9ab998c6b2 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Mon, 29 Jul 2024 11:29:45 -0500
Subject: [PATCH] [AMDGPU] Correctly pass the target-id to `ld.lld`

Summary:
The `ld.lld` linker handles LTO, but it does not understand the
target-id syntax some AMDGPU targets use. This patch parses the
target-id and passes the processor name in `-mcpu` and features in
`-mattr`.
---
 clang/lib/Driver/ToolChains/AMDGPU.cpp | 12 +++++++++++-
 clang/test/Driver/amdgpu-toolchain.c   |  6 +++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/AMDGPU.cpp b/clang/lib/Driver/ToolChains/AMDGPU.cpp
index f796c31af8f67..92183ae377516 100644
--- a/clang/lib/Driver/ToolChains/AMDGPU.cpp
+++ b/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -634,7 +634,17 @@ void amdgpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                   C.getDriver().getLTOMode() == LTOK_Thin);
   else if (Args.hasArg(options::OPT_mcpu_EQ))
     CmdArgs.push_back(Args.MakeArgString(
-        "-plugin-opt=mcpu=" + Args.getLastArgValue(options::OPT_mcpu_EQ)));
+        "-plugin-opt=mcpu=" +
+        getProcessorFromTargetID(getToolChain().getTriple(),
+                                 Args.getLastArgValue(options::OPT_mcpu_EQ))));
+
+  // Always pass the target-id features to the LTO job.
+  std::vector<StringRef> Features;
+  getAMDGPUTargetFeatures(C.getDriver(), getToolChain().getTriple(), Args,
+                          Features);
+  if (!Features.empty())
+    CmdArgs.push_back(
+        Args.MakeArgString("-plugin-opt=-mattr=" + llvm::join(Features, ",")));
 
   addGPULibraries(getToolChain(), Args, CmdArgs);
 
diff --git a/clang/test/Driver/amdgpu-toolchain.c b/clang/test/Driver/amdgpu-toolchain.c
index ebd1158b63074..b60d31bae6270 100644
--- a/clang/test/Driver/amdgpu-toolchain.c
+++ b/clang/test/Driver/amdgpu-toolchain.c
@@ -18,12 +18,12 @@
 // AS_LINK_UR: "-cc1as"
 // AS_LINK_UR: ld.lld{{.*}} "--no-undefined"{{.*}} "--unresolved-symbols=ignore-all"
 
-// RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
+// RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx90a:xnack+:sramecc- -nogpulib \
 // RUN:   -L. -flto -fconvergent-functions %s 2>&1 | FileCheck -check-prefixes=LTO,MCPU %s
-// RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
+// RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx90a:xnack+:sramecc- -nogpulib \
 // RUN:   -L. -fconvergent-functions %s 2>&1 | FileCheck -check-prefix=MCPU %s
 // LTO: clang{{.*}} "-flto=full"{{.*}}"-fconvergent-functions"
-// MCPU: ld.lld{{.*}}"-L."{{.*}}"-plugin-opt=mcpu=gfx906"
+// MCPU: ld.lld{{.*}}"-L."{{.*}}"-plugin-opt=mcpu=gfx90a"{{.*}}"-plugin-opt=-mattr=-sramecc,+xnack"
 
 // RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
 // RUN:   -fuse-ld=ld %s 2>&1 | FileCheck -check-prefixes=LD %s